All Vocab Flashcards
Abscisic Acid (ABA)
A plant hormone that generally acts to inhibit growth, promote dormancy, and help the plant tolerate stressful situations
Absorption Spectrum
The range of a pigment’s ability to absorb various wavelengths of light
Abyssal Zone
The portion of the ocean floor where light does not penetrate and where temperatures and cool and pressures intense
Acclimatization
Physiological adjustment to change in an environmental factor
Accomodation
The automatic adjustment of an eye to focus on near objects
Acetyl CoA
The entry compound for the Krebs cycle in cellular respiration; formed from a fragment of pyruvate attached to a coenzyme
Acetylcholine
One of the most common neurotransmitters; functions by binding to receptors and altering the permeability of the postsynaptic membrane to specific ions, either depolarized or hyperpolarizing the membrane
Acid
A substance that increases the hydrogen ion concentration in a solution
Acid Precipitation
Rain, snow, or fog that is more acidic than pH 5.6
Acoelomate
A solid-bodied animal lacking a cavity between the gut and outer body wall
Acrosome
An organelle at the tip of a sperm cell that helps the sperm penetrate the egg
Actin
A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells
Action Potential
A rapid change in the membrane potential of an excitable cell, caused by stimulus-triggered, selective opening and closing of voltage-sensitive gates in sodium and potassium ion channels
Active Site
The specific proportion of an enzyme that attaches to the substrate by means of weak chemical bonds
Active Transport
The movement of a substance across a biological membrane against its concentration or electrochemical gradient, with the help of energy input and specific transport proteins
Adaptive Peak
An equilibrium state in a population when the gene pool has allele frequencies that maximize the average fitness of a population’s members
Adaptive Radiation
The emergence of numerous species from a common ancestor introduced into an environment, presenting a diversity of new opportunities and problems
Adenylyl Cyclase
An enzyme that converts ATP to cyclic AMP in response to a chemical signal
Adrenal Gland
An endocrine gland located adjacent to to the kidney in mammals; composed of two glandular portions: an outer cortex, which responds to endocrine signals in reacting to stress and effecting salt and water balance, and a central medulla, which responds to nervous inputs resulting from stress
Aerobic
Containing oxygen; referring to an organism, environment, or cellular process that requires oxygen